A plant-based diet is a diet consisting mostly or entirely of foods derived from plants, including vegetables, grains, nuts, seeds, legumes and fruits, and with few or no animal products. A plant based-diet is not necessarily vegetarian. The use of the phrase plant-based has changed over time, and examples can be found of the phrase "plant-based diet" being used to refer to vegan diets, which contain no food from animal sources, to vegetarian diets which may include dairy or eggs but no meat, and to diets with varying amounts of animal-based foods, such as semi-vegetarian diets which contain small amounts of meat. The Academy of Nutrition and Dietetics issued a position statement proposing that well-planned plant diets support health and are appropriate throughout life, including pregnancy, lactation, childhood, adulthood, and for athletes.
As of the early 21st century, it was estimated that four billion people live primarily on a plant-based diet, some because of limits caused by shortages of cropland, freshwater, and energy resources. In Europe, consumption of plant-based meat substitutes was 40% of the world market in 2019, with sales forecast to grow by 60% through 2025 due mainly to concerns for health, food security, and animal welfare. In the United States during 2019, the retail market for plant-based foods was growing at eight times the rate of the general retail food market